HELP! We need pneumatic wiring help!

[BrittanyV]

Our electrical/ programming team is basically completely new this year and we have no clue what so ever as to how to wire an SMC valve (The one that will stop halfway through the stroke). We desperately need detailed instructions on how to do this. We've looked at other posts, and we just cannot figure it out. Please help! Ship is way too close for this! We really need anyone's help, ASAP.

Please, we're begging you!

[DarkJedi613]

Which SMC valve are you referring to? I'm not aware of any valve that is in the kit that can stop halfway through a stroke. If you need two positions the easiest way (in my opinion) would be to use two pneumatic cylinders on different valves.

I'm not exactly sure what you're asking, however, could you provide more information please? Thanks.

[kevin.li.rit]

Hmm I believe you mean the double solenoid? You wire each of the red wires to the M+ and M- on the spike and the two black wires to the ground.

[TubaMorg]

Yes the above post is correct, however this valve alone isn't enough to stop a cylinder stroke midway. You should use another double solenoid valve so that one valve controls the air into the cylinder and the other valve controls the exhaust. You see you need to lock the air in the exhaust side to stop the cylinder mid stroke. Check out this post:

http://www.chiefdelphi.com/forums/sh...ght=pneumatics

Post #11 has a simple diagram that shows you how to do it.

Good luck!

[MattK]

Originally Posted by TubaMorg

Yes the above post is correct, however this valve alone isn't enough to stop a cylinder stroke midway. You should use another double solenoid valve so that one valve controls the air into the cylinder and the other valve controls the exhaust. You see you need to lock the air in the exhaust side to stop the cylinder mid stroke. Check out this post:

http://www.chiefdelphi.com/forums/sh...ght=pneumatics

Post #11 has a simple diagram that shows you how to do it.

Good luck!

This is how CHAOS has done it in years past with positive results.

[BrittanyV]

Originally Posted by TubaMorg

Yes the above post is correct, however this valve alone isn't enough to stop a cylinder stroke midway. You should use another double solenoid valve so that one valve controls the air into the cylinder and the other valve controls the exhaust. You see you need to lock the air in the exhaust side to stop the cylinder mid stroke. Check out this post:

http://www.chiefdelphi.com/forums/sh...ght=pneumatics

Post #11 has a simple diagram that shows you how to do it.

Good luck!

I'm pretty sure that this valve alone is enough. We had it on the bench and we were stopping the piston halfway through with the orange buttons.

[BrittanyV]

Originally Posted by Coffeeism

Hmm I believe you mean the double solenoid? You wire each of the red wires to the M+ and M- on the spike and the two black wires to the ground.

OK, I'm going to show my ignorance. When you say each, does one red wire go to positive and one go to negative? And the black to ground, exactly where do you attach it, to M-? to the fuse block? Sorry, I'm just not sure what to do!

-Brittany

[kevin.li.rit]

Originally Posted by BrittanyV

OK, I'm going to show my ignorance. When you say each, does one red wire go to positive and one go to negative? And the black to ground, exactly where do you attach it, to M-? to the fuse block? Sorry, I'm just not sure what to do!

-Brittany

Yes, one red wire is going to M+ the other will red wire will go to M-, the Black Wires you can connect to the ground on the fuseboard.

[BrittanyV]

Thanks a lot.

[Suicidesurfer]

If you wanna know anything about pneumatic contact this screen name: pielesuave....he is on team 75 and will be able to help you

[Dad1279]

Originally Posted by BrittanyV

I'm pretty sure that this valve alone is enough. We had it on the bench and we were stopping the piston halfway through with the orange buttons.

You need two valves. One for direction, which you hook up normally. Then you connect the vents from the first valve to a second, to stop the air from venting to the atmosphere. This stops the cylinder from moving until this second valve is opened.

Program the first for direction, the second for movement(on/off)

[DonRotolo]

Originally Posted by Dad1279

You need two valves. One for direction, which you hook up normally. Then you connect the vents from the first valve to a second, to stop the air from venting to the atmosphere. This stops the cylinder from moving until this second valve is opened.

Program the first for direction, the second for movement(on/off)

This will work fine. Last year we found a better solution, called a "Three-position pressure center" valve. The spec sheet is here. Look at valve type SY3520-6H, for example.

This kind of valve has three positions, and uses two solenoids: Position 1 is extend, Position 2 is hold, and Position 3 is retract. One solenoid is Extend, the other is Retract, and when neither is energized it means Hold. (This can and should be controlled with a single spike as explained by coffeeism above).

We selected "Pressure Center" types, which apply full pressure to both sides of the cylinder when in the Hold position. You can also choose "Closed Center", which closes off all air to the cylinder. You don't want "Vent Center", which will allow the piston to move freely in the "Hold" (center) position.

One important thing we learned last year: Pistons work best in 'this end or that end' applications - they do not work well for non-endpoint positioning. The problem is that any variation in load causes the piston to move, because it's only air, and that will often cause a problem.

Good luck. I hope this post helps anyone considering midpoint positioning of pneumatic cylinders.

Don

[TubaMorg]

Originally Posted by Don Rotolo

This will work fine. Last year we found a better solution, called a "Three-position pressure center" valve. The spec sheet is here. Look at valve type SY3520-6H, for example.

This kind of valve has three positions, and uses two solenoids: Position 1 is extend, Position 2 is hold, and Position 3 is retract. One solenoid is Extend, the other is Retract, and when neither is energized it means Hold. (This can and should be controlled with a single spike as explained by coffeeism above).

We selected "Pressure Center" types, which apply full pressure to both sides of the cylinder when in the Hold position. You can also choose "Closed Center", which closes off all air to the cylinder. You don't want "Vent Center", which will allow the piston to move freely in the "Hold" (center) position.

One important thing we learned last year: Pistons work best in 'this end or that end' applications - they do not work well for non-endpoint positioning. The problem is that any variation in load causes the piston to move, because it's only air, and that will often cause a problem.

Good luck. I hope this post helps anyone considering midpoint positioning of pneumatic cylinders.

Don

Whoa! Correct me if I'm wrong, but I thought the use of "alternative" solenoid valves is prohibited! How'd you get away with that? Of course there are valves out there that can control mid-stroke positioning, but we are only allowed to use the solenoids in the kit. You are right, though, that the compressability of air makes positioning pretty iffy...definitely no precision there without a more complex feedback mechanism (such as a pot).

[Dad1279]

Originally Posted by TubaMorg

Whoa! Correct me if I'm wrong, but I thought the use of "alternative" solenoid valves is prohibited! How'd you get away with that? Of course there are valves out there that can control mid-stroke positioning, but we are only allowed to use the solenoids in the kit. You are right, though, that the compressability of air makes positioning pretty iffy...definitely no precision there without a more complex feedback mechanism (such as a pot).

I thought the same, but a quick search of last years rules seems to allow it.

I will disagree about the positioning, however. We used it to lift our main arms last year, and it worked well enough to seed 1st at VCU and 2nd NJ Fast, strong, simple and precise enough to lift and position the tetras.

However everything has a place, and this year we use no pneumatics.